BAL-FZ
Most severe Bushfire Attack Level, the Flame Zone, where radiant heat flux exceeds 40 kW/m squared and direct flame contact is expected during a bushfire.
Flame Zone classification under AS 3959, applied to sites where predicted radiant heat flux exceeds 40 kW/m squared and direct flame contact is anticipated. BAL-FZ construction must be tested as a complete system: external walls, windows, doors, decks, and roofs typically use non-combustible masonry, concrete, or proprietary tested assemblies. External glazing must be bushfire-shutter protected or tested to withstand BAL-FZ flame exposure. The cost premium over standard construction is significant. Some local councils restrict or prohibit new building in BAL-FZ areas. For buyers, every external element must come with a test certificate showing compliance with the BAL-FZ requirements of AS 3959. Allow generous lead times and coordinate closely with the building surveyor and bushfire consultant from the design stage.
Values and references on this page are indicative and drawn from common industry sources. Always verify the current AS/NZS standard, manufacturer data sheet or NIAA policy publication before relying on figures for design, specification or compliance work.
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